JP5428994B2 - Anomaly diagnosis method, apparatus and program for machine equipment - Google Patents

Description

  The present invention relates to an abnormality diagnosis method, apparatus, and program for machine equipment that diagnoses the degree of abnormality using high-frequency vibration generated from the machine equipment.

  In mechanical equipment, it is known that when a mechanical element such as a bearing is damaged or missing, the amplitude of high-frequency vibration of approximately 1 kHz or more is increased as compared with the normal state. In view of this, an amplitude modulation component caused by bearing damage or the like is extracted by using a natural vibration component such as a bearing block as a carrier, and the amplitude value is analyzed and evaluated.

  Conventionally, a method of diagnosing the degree of abnormality of mechanical equipment and mechanical elements has been performed using the amplitude change of the high-frequency vibration. Non-Patent Document 1 discloses that a bearing abnormality is diagnosed using an average value (absolute value average value) of a waveform (absolute value processing waveform) after the absolute value processing of a vibration waveform. Patent Document 1 discloses diagnosing the degree of abnormality of a bearing using a peak value (maximum value) of the cube of a vibration value.

JP 11-337450 A

Toshio Toyoda “Proceedings of Rotating Machine Diagnosis” (Japan Plant Maintenance Association, 1991 first edition, p.232 to p.234 and p.247 to p.248)

  However, the conventional method has the following problems. That is, in the abnormality diagnosis method of Non-Patent Document 1, the amplitude offset (DC) + amplitude modulation component (AC) waveform, that is, the waveform including the amplitude offset is directly used for the vibration of the high frequency vibration (carrier) processed. Amplitude parameters such as absolute value average values are calculated. However, if an abnormality such as bearing damage occurs, the component corresponding to the amplitude offset does not change so much, and only the amplitude of the periodic shock vibration corresponding to the amplitude modulation component greatly increases. Therefore, there is a concern that the abnormality diagnosis capability may be lowered by including an amplitude offset which is a vibration component that does not change so much in the evaluation.

  In addition, in the bearing abnormality diagnosis method disclosed in Patent Document 1, a peak value that originally has a large variation compared to the average value is used, and the amplitude value is raised to the third power to further increase the variation. There was a drawback that the stability of the could not be maintained.

  The present invention has been made to compensate for the drawbacks of the conventional methods described above, and an object thereof is to make it possible to accurately diagnose the degree of abnormality of mechanical equipment.

An abnormality diagnosis method for mechanical equipment according to the present invention is an abnormality diagnosis method for mechanical equipment that diagnoses an abnormality by measuring vibration of the mechanical equipment, the absolute value processing of the measured vibration signal, and the absolute value processing. An envelope processing step of the vibration signal; an amplitude average value of the vibration signal subjected to the envelope processing; a step of calculating an amplitude parameter of the vibration signal from which the amplitude average value has been removed; and the calculated amplitude parameter. And a preset allowable value, and if the calculated amplitude parameter is larger than the allowable value, a step of diagnosing that an abnormality has occurred in the mechanical equipment is included.
An abnormality diagnosis method for mechanical equipment according to the present invention is an abnormality diagnosis method for mechanical equipment that diagnoses an abnormality by measuring vibration of the mechanical equipment, the absolute value processing of the measured vibration signal, and the absolute value processing. removing the average amplitude value of the vibration signal is compared with the step of calculating the amplitude parameters of the vibration signal obtained by removing the amplitude average value, the allowable value and a preset amplitude parameters the calculated, the calculated amplitude And a step of diagnosing that an abnormality has occurred in the mechanical equipment when the parameter is larger than the allowable value.
Another feature of the abnormality diagnosis method for mechanical equipment according to the present invention is that a high-frequency vibration signal is extracted from the measured vibration signal, and the above steps are executed on the high-frequency vibration signal.
Another feature of the abnormality diagnosis method for mechanical equipment according to the present invention is that an absolute value average value or a maximum value is used as the amplitude parameter.
Another feature of the abnormality diagnosis method for machine equipment according to the present invention is that the machine equipment is a bearing which is a machine element.
An abnormality diagnosis apparatus for mechanical equipment according to the present invention is an abnormality diagnosis apparatus for mechanical equipment for diagnosing an abnormality by measuring vibration of the mechanical equipment, wherein the absolute value processing is performed on the measured vibration signal. Means for envelope processing of a vibration signal; means for removing an amplitude average value of the vibration signal subjected to the envelope processing; means for calculating an amplitude parameter of the vibration signal from which the amplitude average value has been removed; and the calculated amplitude parameter And a preset allowable value, and when the calculated amplitude parameter is larger than the allowable value, there is provided a means for diagnosing that an abnormality has occurred in the mechanical equipment.
An abnormality diagnosis apparatus for mechanical equipment according to the present invention is an abnormality diagnosis apparatus for mechanical equipment for diagnosing an abnormality by measuring vibration of the mechanical equipment, wherein the absolute value processing is performed on the measured vibration signal. and means for removing the amplitude average value of the vibration signal, compares the means for calculating the amplitude parameters of the vibration signal obtained by removing the amplitude average value, the allowable value and a preset amplitude parameters the calculated, the calculated amplitude And a means for diagnosing that an abnormality has occurred in the mechanical equipment when the parameter is larger than the allowable value.
The program of the present invention is a program for diagnosing an abnormality by measuring vibration of mechanical equipment, and processing for absolute value processing of the measured vibration signal and processing for envelope processing of the vibration signal subjected to the absolute value processing A process of removing an amplitude average value of the vibration signal subjected to the envelope processing, a process of calculating an amplitude parameter of the vibration signal from which the amplitude average value has been removed, and the calculated amplitude parameter and a preset allowable value. In comparison, when the calculated amplitude parameter is larger than the allowable value, the computer is caused to execute a process of diagnosing that an abnormality has occurred in the mechanical equipment.
The program of the present invention is a program for diagnosing an abnormality by measuring vibrations of mechanical equipment, and processing for absolute value processing of the measured vibration signal and removal of the amplitude average value of the vibration signal subjected to the absolute value processing The process of calculating the amplitude parameter of the vibration signal from which the amplitude average value is removed, and the calculated amplitude parameter are compared with a preset allowable value, and the calculated amplitude parameter is greater than the allowable value In this case, the computer is caused to execute a process of diagnosing that an abnormality has occurred in the mechanical equipment.

  According to the present invention, it is possible to recognize a slight amplitude change at the beginning of an abnormality, and it is possible to diagnose an abnormality of a mechanical facility having a small variation and stability. In other words, when there is a restriction on the sensor mounting site or when the amplitude of abnormal vibration is low due to a relatively slow rotation speed, etc., the threshold value determination according to the conventional method may overdetect by noise. Since the threshold can be set higher than the amplitude, overdetection can be prevented.

It is a block diagram which shows schematic structure of the abnormality diagnosis apparatus of the mechanical installation which concerns on 1st Embodiment. It is a block diagram which shows schematic structure of the abnormality diagnosis apparatus of the mechanical installation which concerns on 2nd Embodiment. It is a figure which shows an example of the high frequency vibration waveform detected from the normal bearing. It is a figure which shows an example of the absolute value processing waveform of the high frequency vibration of FIG. It is a figure which shows an example of the envelope waveform of the absolute value processing waveform of FIG. It is a figure which shows an example of the high frequency vibration waveform detected from the abnormal bearing. Is a diagram illustrating an example of the absolute value processing waveform of the high frequency vibration of FIG. Is a diagram illustrating an example of the envelope waveform of the absolute value processing waveform in FIG. It is a figure which shows an example of abnormality determination capability comparison with the method of this invention, and the method of a prior art. It is a figure which shows another example of abnormality determination capability comparison with the method of this invention, and the method of a prior art. FIG. 5 is a diagram illustrating an example of an AC coupling waveform of the absolute value processing waveform of FIG. 4. Is a diagram illustrating an example of the AC coupling waveform of the absolute value processing waveform in FIG. It is a figure which shows another example of abnormality determination capability comparison with the method of this invention, and the method of a prior art. It is a figure which shows another example of abnormality determination capability comparison with the method of this invention, and the method of a prior art. It is a figure which shows the pump of Example 1, and a vibration measurement site | part. It is a figure which shows the steel material rolling mill of Example 4, and a vibration measurement site | part.

  In the present invention, only the amplitude modulation component (AC coupled waveform) from which the amplitude offset of the high frequency vibration signal is removed is used to evaluate the amplitude of the high frequency vibration signal. That is, a high-frequency vibration signal (also referred to as a full-wave rectification waveform) obtained by performing absolute value processing on a high-frequency vibration signal (usually a vibration acceleration signal) that is preferably obtained by passing through a high-pass filter or a band-pass filter. ), And after performing envelope processing, the amplitude offset is removed. The frequency of the high-frequency vibrations extracted here is 1 kHz or more, preferably 10 kHz or more, and the lower limit frequency varies depending on the target machine / equipment.

Using the high-frequency vibration signal (AC coupling envelope waveform) obtained in this way, the absolute value average value (AVE) represented by the equation (1), the maximum value (PEAK) represented by the equation (2). Amplitude parameters such as Here, in each of the expressions (1) and (2), the middle side corresponds to analog data calculation, and the right side corresponds to digital data calculation. x (t) and x _k are vibration data, | · | is the absolute value of the data, T and N are calculation intervals, and max [·] is the maximum value in the data. The calculated amplitude parameter is compared with a preset allowable value for each amplitude parameter, and when the calculated amplitude parameter is larger than the allowable value, the diagnosis target mechanical equipment is determined to be abnormal.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.
(First embodiment)
FIG. 1 is a block diagram showing a schematic configuration of an abnormality diagnosis apparatus for machine equipment according to the first embodiment. With reference to FIG. 1, the abnormality diagnosis apparatus of a mechanical installation and the abnormality diagnosis method by it are demonstrated.

  The input unit 1 receives a vibration signal detected in the vicinity of a bearing that is a mechanical element of a mechanical facility such as a pump that is a diagnosis target mechanical facility. The vibration signal input to the input unit 1 is amplified by the amplifier 3 or the like after the DC component is removed by the DC component removal unit 2.

  The high-frequency vibration extraction unit 4 (band-pass filter) is provided with frequency restrictions according to specifications such as the bearing type and vibration detection position of the machine equipment to be diagnosed, and extracts a high-frequency vibration signal. At this time, instead of the band limiting filter that specifies the lower limit and the upper limit of the pass frequency, a high-pass filter that specifies only the lower limit may be used. Further, when the low frequency component of the vibration signal itself is sufficiently small, the high frequency vibration extraction unit 4 can be omitted. FIG. 3 illustrates a high-frequency vibration waveform that has passed through a band-pass filter having a lower limit of the pass frequency of 10 kHz and an upper limit of 40 kHz.

  The absolute value processing unit 5 performs full-wave rectification on the high-frequency vibration signal extracted by the high-frequency vibration extraction unit 4 to obtain an absolute value processing waveform. FIG. 4 illustrates an absolute value processing waveform. The envelope processing unit 6 (low-pass filter, etc.) is provided with a frequency limit in accordance with the specifications such as the bearing size and the rotational speed of the machine equipment to be diagnosed, and the absolute value processing unit 5 performs the absolute value processing. Envelope the signal. FIG. 5 illustrates a high-frequency vibration waveform (envelope waveform) that has been subjected to envelope processing and passed through a low-pass filter having an upper frequency limit of 1 kHz.

The amplitude offset removal unit 7 removes the amplitude offset of the high-frequency vibration signal subjected to the envelope processing by the envelope processing unit 6 using an amplitude average value removal, a low-frequency removal filter, or the like, and creates an AC coupled envelope waveform .

  In the amplitude parameter calculation unit 8, the amplitude parameter such as the absolute value average value (AVE) of the equation (1) and the maximum value (PEAK) of the equation (2) is obtained with respect to the AC coupling envelope waveform created by the amplitude offset removal unit 7. calculate. In the abnormality determination unit 10, the amplitude parameter calculated by the amplitude parameter calculation unit 8 is compared with an allowable value relating to each amplitude parameter set in advance and stored in the amplitude allowable value storage unit 9, and the calculated amplitude parameter is an allowable value. If it is larger, it is determined that the diagnosis target mechanical equipment is abnormal.

3 to 5 are vibration acceleration waveforms detected and processed from the bearing block of a normal cylindrical roller bearing of the pump.

(Second Embodiment)
FIG. 2 is a block diagram showing a schematic configuration of an abnormality diagnosis apparatus for mechanical equipment according to the second embodiment. With reference to FIG. 2, an abnormality diagnosis apparatus for a mechanical facility and an abnormality diagnosis method using the apparatus will be described.

  A vibration signal detected in the vicinity of a bearing portion, which is a mechanical element of a mechanical facility such as a pump that is a diagnosis target mechanical facility, is input to the input unit 1A. The vibration signal input to the input unit 1A is amplified by the amplifier 3A after the DC component is removed by the DC component removal unit 2A.

  The high-frequency vibration extraction unit 4A (bandpass filter) is provided with a frequency limit according to specifications such as the bearing type and vibration detection position of the machine equipment to be diagnosed, and extracts a high-frequency vibration signal. At this time, instead of the band limiting filter that specifies the lower limit and the upper limit of the pass frequency, a high-pass filter that specifies only the lower limit may be used. Further, when the low frequency component of the vibration signal itself is sufficiently small, the high frequency vibration extraction unit 4A can be omitted.

  In the absolute value processing unit 5A, the high frequency vibration signal extracted by the high frequency vibration extraction unit 4A is full-wave rectified to obtain an absolute value processing waveform.

In the amplitude offset removing unit 6A, the amplitude offset generated in the absolute value processing unit 5A is removed by an amplitude average value removal, a low-frequency removal filter, or the like to create an AC coupled absolute value waveform.

In the amplitude parameter calculation unit 7A, amplitude parameters such as the absolute value average value (AVE) of the equation (1) and the maximum value (PEAK) of the equation (2) are obtained with respect to the AC coupled absolute value waveform created by the amplitude offset removal unit 6A. calculate. In the abnormality determination unit 9A, the amplitude parameter calculated by the amplitude parameter calculation unit 7A is compared with an allowable value for each amplitude parameter that is set in advance and stored in the amplitude allowable value storage unit 8A, and the calculated amplitude parameter is an allowable value. If it is larger, it is determined that the diagnosis target mechanical equipment is abnormal.

6 to 8 show vibration acceleration waveforms detected and processed from the bearing block when the cylindrical roller bearing of the pump speed reducer taken in FIGS. 3 to 5 is damaged. FIG. 15 shows the pump and vibration measurement site of Example 1. The processing contents, 6 3 and the same, FIG. 7 is 4 and the same, FIG. 8 is identical to FIG. FIG. 9 shows the ratio of the amplitude parameter obtained by using the equation (1) from the AC coupling envelope waveform from which the amplitude average value is removed by the method of the present invention, that is, the vibration of the abnormal bearing and the normal bearing by the method of the present invention. the ratio of the absolute value calculated from the signal mean value (AVE), by the method of the prior art, FIG. 8 and the absolute value average calculated from the vibration signal of abnormal bearing and normal bearing obtained from the waveform of FIG. 5 (AVE) The ratio is compared. Here, since the allowable value is set to 4, abnormality determination can be sufficiently performed by the method of the present invention, but abnormality determination cannot be performed by the method of the prior art. Although the bearing needed to be replaced immediately, the method of the present invention can reliably determine the replacement, whereas the method of the prior art cannot determine the replacement. From this, it can be seen that by using the method of the present invention, an abnormality such as bearing damage can be diagnosed with high accuracy.

FIG. 10 shows the ratio of the amplitude parameter obtained by using the equation (2) from the AC coupling envelope waveform from which the amplitude average value is removed by the method of the present invention, that is, the vibration of the abnormal bearing and the normal bearing by the method of the present invention. the ratio of the maximum value calculated from the signal (PEAK), by the method of the prior art, and comparing the ratio of the maximum value calculated from the vibration signal of abnormal bearing and normal bearing obtained from the waveform of FIG. 7 and FIG. 4 (PEAK) Is. As in the case of the first embodiment, the allowable value is set to 4, so that the abnormality determination can be sufficiently performed by the method of the present invention, but the abnormality determination cannot be performed by the conventional method. From this, it can be seen that by using the method of the present invention, an abnormality such as bearing damage can be diagnosed with high accuracy.

FIG. 13 shows the AC coupled absolute value processing by removing the average amplitude value for each of FIG. 7 which is the absolute value processing waveform of the abnormal bearing and FIG. 4 which is the absolute value processing waveform of the normal bearing by the method of the present invention. 12 and FIG. 11 after forming the waveform, the ratio of the amplitude parameter obtained by using the equation (1), that is, the absolute value average value calculated from the vibration signal of the abnormal bearing and the normal bearing by the method of the present invention. The ratio of (AVE) is compared with the ratio of the average absolute value (AVE) calculated from the vibration signals of the abnormal bearing and the normal bearing by the method of the prior art. Since the allowable value is set to 4, abnormality determination is possible with the method of the present invention, but abnormality determination cannot be performed with the method of the prior art. From this, it can be seen that by using the method of the present invention, an abnormality such as bearing damage can be diagnosed with high accuracy.

FIG. 14 shows the average value (AVE) calculated by the method of the present invention and the average absolute value calculated by the method of the prior art by measuring the vibration in the vicinity of the bearing of the steel rolling mill approximately once a month. The change tendency is graphed with the ratio (relative amplitude value) of the values (AVE) set to AVE = 1 for the normal amplitude value at the initial stage of use of the bearing. In FIG. 16 , the steel material rolling machine and vibration measurement site | part of Example 4 are shown. The bearing was replaced in early December, and it was confirmed that fatal flaking occurred. Since the allowable value was set to 3, the method of the present invention was able to determine the abnormality at the time of September, but the conventional method can barely determine the abnormality in November, and preparation for bearing replacement is in time. There was no situation. From this, it can be seen that by using the method of the present invention, an abnormality called bearing damage can be detected at an early stage.

  The machine equipment abnormality diagnosis apparatus to which the present invention is applied can be specifically configured by a computer system including a CPU, a ROM, a RAM, and the like, and is realized by the CPU executing a program. Moreover, the abnormality diagnosis apparatus for mechanical equipment to which the present invention is applied may be composed of a single device or a plurality of devices.

  The object of the present invention can also be achieved by supplying, to the system or apparatus, a storage medium in which a program code of software that realizes a function of performing abnormality diagnosis of mechanical equipment as described above is recorded. In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the program code itself and the storage medium storing the program code constitute the present invention. As a storage medium for supplying the program code, for example, a flexible disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a CD-R, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.

  INDUSTRIAL APPLICABILITY The present invention is useful for smoothly promoting maintenance activities such as repair of machine equipment, replacement of machine components that are constituent elements thereof, and inspection during operation of machine equipment.

DESCRIPTION OF SYMBOLS 1, 1A: Input part 2, 2A: DC component removal part 3, 3A: Amplifier 4, 4A: High frequency vibration extraction part 5, 5A: Absolute value processing part 6: Envelope processing 7, 6A: Amplitude offset removal part 8, 7A: Amplitude parameter calculation unit 9, 8A: Allowable amplitude storage unit 10, 9A: Abnormality determination unit

Claims (9)

An abnormality diagnosis method for mechanical equipment for diagnosing abnormality by measuring vibration of mechanical equipment,
An absolute value processing of the measured vibration signal;
An envelope processing of the absolute value processed vibration signal;
Removing the amplitude average value of the envelope-processed vibration signal;
Calculating an amplitude parameter of the vibration signal from which the amplitude average value is removed;
Comparing the calculated amplitude parameter with a preset allowable value, and when the calculated amplitude parameter is larger than the allowable value, there is a step of diagnosing that an abnormality has occurred in the mechanical equipment. An abnormality diagnosis method for machine equipment. An abnormality diagnosis method for mechanical equipment for diagnosing abnormality by measuring vibration of mechanical equipment,
An absolute value processing of the measured vibration signal;
Removing the amplitude average value of the absolute value processed vibration signal;
Calculating an amplitude parameter of the vibration signal from which the amplitude average value is removed;
Comparing the calculated amplitude parameter with a preset allowable value, and when the calculated amplitude parameter is larger than the allowable value, there is a step of diagnosing that an abnormality has occurred in the mechanical equipment. An abnormality diagnosis method for machine equipment.   3. The method of diagnosing an abnormality of a mechanical facility according to claim 1, wherein a high-frequency vibration signal is extracted from the measured vibration signal, and each of the steps is performed on the high-frequency vibration signal.   The abnormality diagnosis method for mechanical equipment according to any one of claims 1 to 3, wherein an absolute value average value or a maximum value is used as the amplitude parameter.   5. The abnormality diagnosis method for a machine facility according to any one of claims 1 to 4, wherein the machine facility is a bearing that is a machine element. An abnormality diagnosis device for mechanical equipment that diagnoses abnormalities by measuring vibrations of mechanical equipment,
Means for absolute value processing of the measured vibration signal;
Means for enveloping the absolute value processed vibration signal;
Means for removing an amplitude average value of the envelope-processed vibration signal;
Means for calculating an amplitude parameter of the vibration signal from which the amplitude average value is removed;
Comparing the calculated amplitude parameter with a preset allowable value, and when the calculated amplitude parameter is larger than the allowable value, there is provided means for diagnosing that an abnormality has occurred in the mechanical equipment. An abnormality diagnosis device for machine equipment. An abnormality diagnosis device for mechanical equipment that diagnoses abnormalities by measuring vibrations of mechanical equipment,
Means for absolute value processing of the measured vibration signal;
Means for removing an average amplitude value of the absolute value processed vibration signal;
Means for calculating an amplitude parameter of the vibration signal from which the amplitude average value is removed;
Comparing the calculated amplitude parameter with a preset allowable value, and when the calculated amplitude parameter is larger than the allowable value, there is provided means for diagnosing that an abnormality has occurred in the mechanical equipment. An abnormality diagnosis device for machine equipment. A program for diagnosing abnormalities by measuring vibrations of mechanical equipment,
Processing the absolute value of the measured vibration signal;
A process of performing envelope processing on the absolute value processed vibration signal;
A process of removing an average amplitude value of the vibration signal subjected to the envelope processing;
A process of calculating an amplitude parameter of the vibration signal from which the amplitude average value is removed;
The calculated amplitude parameter is compared with a preset allowable value, and if the calculated amplitude parameter is larger than the allowable value, the computer is caused to perform a process of diagnosing that an abnormality has occurred in the mechanical equipment. Program for. A program for diagnosing abnormalities by measuring vibrations of mechanical equipment,
Processing the absolute value of the measured vibration signal;
A process for removing an amplitude average value of the absolute value processed vibration signal;
A process of calculating an amplitude parameter of the vibration signal from which the amplitude average value is removed;
The calculated amplitude parameter is compared with a preset allowable value, and if the calculated amplitude parameter is larger than the allowable value, the computer is caused to perform a process of diagnosing that an abnormality has occurred in the mechanical equipment. Program for.

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